Using self-assembly techniques, a team of Chinese researchers have creating a …

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I will start this article by saying something up front: I disliked organic chemistry... immensely. However, one topic that held my interest (for whatever reason) was molecules with large rings in them and what you can do with them. The first exposure I had to such molecules was a discussion about crown ethers, a type of molecule discovered in 1967 by a researcher at the DuPont company—a discovery that would later result in him winning a portion of the Nobel Prize in Chemistry 20 years later. These molecules were some of the first examples of synthetically produced compounds that could recognize specific molecules and ions through structural and chemical interactions. Essentially, crown ethers act as a very simple version of what happens countless time each day in biological systems.

Today, as many scientists seek to develop new nanomaterials that exhibit useful properties, ring molecules represent a class of appealing candidates. Many of the known ring molecules rely on some form of organic backbone, and synthesizing one with an entirely metal structure has remained elusive. Last month, in the online edition of Angewandte Chemie International Edition an article published by a group of Chinese chemists described the work they did in synthesizing a ringed molecule that has a main structure of 36 individual gold atoms all chemically bonded to their gold neighbors.

The ring was constructed using self-assembly techniques, where simple constituents spontaneously assemble themselves into a much more complex structure. There are many routes to forming zeolites that exploit these ideas; one prominent example is where a simple solution containing silica, water, and what is referred to as a structure directing agent, are be mixed and popped in a oven to cook for a set amount of time. With no intervention, a complex crystalline material can emerge.

In the synthesis of this golden nano-crown, the researchers started by forming simpler gold triangles: molecules that contained nothing more than three monovalent gold atoms bound to one another. The next step was to attach an extra gold atom to each point on the triangle, along with organic ligands that made these precursor molecules each look like a "three-blade propeller." At the right concentration, these simpler structures would then self assemble into the much more complex golden ring pictured above.

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Matt Ford
Matt is a contributing writer at Ars Technica, focusing on physics, astronomy, chemistry, mathematics, and engineering. When he's not writing, he works on realtime models of large-scale engineering systems. Emailzeotherm@gmail.com//Twitter@zeotherm